The invention relates to a method of controlling the quality in core or shell shooting machines, wherein a molding material is forced by means of a shooting device into an openable tool and solidified therein to form a component of a mold--core, shell, or the like--and wherein the mold component is removed when the tool is open.
Basically the present invention relates to the field of foundry practice. To produce castings, foundry cores or foundry molds are generally made as separate parts, combined, and joined together to form a casting mold or core assembly. Thereafter, these core assemblies are filled with molten metal for producing, for example, a metallic workpiece. In mass production the core assemblies that are to be filled with molten metal pass one after the other through the production line.
In this connection, it is quite especially important that the workpieces cast in the core assemblies require an extremely long cooling phase, which will often last over several hours. Only after this cooling phase, is it possible to inspect the cast workpiece or product. Consequently, it is possible to find only several hours after casting and, thus, likewise several hours after the core shooting operation, whether or not the part cast in the core assembly is entirely free of defects.
In the event that a defective core is used, it will be possible to detect a reject resulting therefrom during the casting only after hours following the production of the core. Should in this instance the defect on the core again be a systematic, recurrent defect, rejects would be produced for hours before the defect is found on the cast product. The defective cores that are accountable for these rejects may originate, on the one hand, from defects in the tool of the core shooting machine and, on the other hand, from damage that occurs while handling, transporting, or assembling the cores. In any event, it is not justifiable to be able to detect defects and, thus, rejects, only after completion of the casting operation, or during an inspection of the cooled castings.
Core and shell shooting machines of the above-described kind have been known from practice for decades. Only by way of example, reference may be made to DE 31 48 461 C1.
DE 44 34 798 A1 discloses likewise a core and shell shooting machine, in which at least one visual inspection of the tool is provided. In the long run, the visual inspection disclosed in DE 44 34 798 A1 is impractical, inasmuch as the tool cannot be constantly observed, in particular within the scope of a fully automatic production. For a visual inspection, a skilled operator would have to observe the tool constantly, i.e., after each shooting operation. Even if such a visual observation or inspection were to go forward, the destiny of an ejected core that is to be further transported would be left open, since--as aforesaid--defects or damage may also occur while handling, transferring, or even assembling the cores.
It is therefore the object of the present invention to provide a method of controlling quality in core or shell shooting machines, wherein it is possible to recognize rejects and to prevent--systematically--repeating rejects. Furthermore, it is an object to provide an apparatus for shooting cores and shells with the use of the method in accordance with the invention.